scholarly journals Theoretical Studies of the Vibration Process of the Dryer for Waste of Food

2020 ◽  
Vol 44 (339) ◽  
pp. 32-45
Author(s):  
Volodymyr Bulgakov ◽  
Ivan Sevostianov ◽  
Gryhoriy Kaletnik ◽  
Ihor Babyn ◽  
Semjons Ivanovs ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Food Waste ◽  
Experimental Studies ◽  
The Body ◽  
Fluidised Bed ◽  
Technological Parameters ◽  
Heating Pipes ◽  
Maximum Stiffness ◽  
Low Energy Consumption ◽  
The Heat Transfer Coefficient

AbstractAn urgent problem is drying and processing of the wet dispersed waste, obtained in the production of food products, which can then be efficiently used as a fertiliser, for feeding livestock or as biofuel. A new design of a vibrating fluidised bed dryer has been developed, which, with low energy consumption, provides a pre-set productivity and the required final moisture content. The process of vertical oscillations of the body of a vibration dryer, together with the food waste contained in it, is analysed analytically, the necessary equivalent scheme is built, on the basis of which differential equations of the vertical oscillations of the body are compiled, their analytical solutions are obtained, and a numerical calculation is performed on a PC using the developed program. Rational parameters of the vibration dryer, providing vibroboiling of the mass of the food waste, have been determined: the body mass m = 250 ... 510 kg; the debalance mass md= 10… 15 kg; the number of revolutions of the debalance electric motor nd= 1950 ... 2650 rpm ∙ min∙1; maximum stiffness of the support springs Cp= 8∙105 N∙m–1; the diameter of the centre of mass of the debalances dd= 0.01 m. In addition, as a result of the thermophysical theoretical and experimental studies of the vibration drying process, the following optimal design and technological parameters of the vibration dryer were obtained: the heat transfer area St.p.n= 4.15 m2; the radius of the heating pipe rt= 0.1 m; the length of the heating pipe lt = 3 m; the number of heating pipes nt= 50; the heat transfer coefficient Kp= 2500; the final temperature of the dried waste to2= 100 ºС.

scholarly journals Heat transfer in the mold during vertical continuous casting of steel

2018 ◽  
pp. 26-30
Author(s):  
E. I. Marukovich ◽  
E. B. Demchenko
Keyword(s):  
Heat Transfer ◽  
Temperature Regime ◽  
Thermal State ◽  
Effective Means ◽  
Experimental Studies ◽  
Casting Process ◽  
Continuous Casting Of Steel ◽  
Technological Parameters ◽  
Casting Method ◽  
Calculation Technique

The analysis of the performed researches has shown that the offered calculation technique is an effective means of management of formation process in casting. The found dependences and experimental data allow to calculate the specific value of the exactм heat flux in a given range of technological parameters obtained during a series of successful experiments for a particular casting method.Having the results of studies of the temperature regime of the mold during casting of a certain size and profile, it is possible to calculate the thermal state of the mold for the same casting process, but for the production of castings of any other size and profile.Having a certain amount of information on the temperature regime of the mold at different casting methods, you can use the solutions obtained to become the owner of a database containing the necessary information for solving the problems of solidification of the casting. In the subsequent design of equipment and equipment there is no need for additional experimental studies and analysis of the results.

Free Convection, Forced Convection, and Acoustic Vibrations in a Constant Temperature Vertical Tube

1959 ◽  
Vol 81 (1) ◽  
pp. 68-74 ◽  
Author(s):  
T. W. Jackson ◽  
W. B. Harrison ◽  
W. C. Boteler
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Sound Pressure ◽  
Experimental Studies ◽  
Experimental System ◽  
Vertical Tube ◽  
Acoustic Vibrations ◽  
Average Temperature ◽  
Comparison Of The Results ◽  
The Heat Transfer Coefficient

Experimental studies of heat transfer to air with superposed forced and free convection were reported in a previous paper [1]. In studies reported in this paper, the same experimental system was employed, but a complication was added in the form of acoustic vibrations in the flow field. By comparison of the results with and without acoustic vibrations under conditions which were otherwise the same, an effort has been made to determine the effect of acoustic vibrations on heat transfer. The Nusselt modulus, based on the log mean temperature difference, ranged from 17.2 to 50.6; the Graetz modulus, based on the bulk or average temperature of the air, ranged from 40.2 to 1633; and the Grashof-Prandtl D/L modulus, based on properties of air at the wall temperature, ranged from 0.967 × 105 to 1.26 × 106. The results indicated that sound pressure levels below approximately 118 decibels had little effect on the heat-transfer coefficient. Below 118 decibels free convection forces were evident. Above 118 decibels free convection forces were apparently negligible and the effect of sound appeared to be considerable.

The Deformation Rule of the Cooled U75V Heavy Rail Caused by the Different Heat Transfer Coefficient

2011 ◽  
Vol 299-300 ◽  
pp. 1005-1011 ◽  
Author(s):  
Ming Xin Gao ◽  
Pei Long Wang ◽  
Hao Jia ◽  
Shan Hu Tong ◽  
Hua Song ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
High Speed ◽  
Reference Value ◽  
Ansys Software ◽  
Cooling Process ◽  
Technological Parameters ◽  
The Heat Transfer Coefficient ◽  
Heavy Rail

When rolled heavy rail is on the cooling bed for natural cooling, the heat transfer coefficient has important effect on the bending and section sizes of cooled heavy rail. In the paper, the heat-stress couple module ofANSYS software is adopted to carry on numerical simulation on the cooling process of 60kg/m U75V heavy rail, and we obtain the change rule that heat transfer coefficient has effect on bending curvature and section sizes of cooled heavy rail. This study is of great reference value on cooling bed design and the formulation of cooling technological parameters for high speed heavy rail.

scholarly journals Effect of measurement errors in determining the heat transfer coefficient of the enclosing structures of an isothermal car

2019 ◽  
Vol 78 (2) ◽  
pp. 100-104 ◽  
Author(s):  
A. A. GOLUBIN ◽  
N. V. BELOVA ◽  
S. N. NAUMENKO
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Measurement Errors ◽  
The Body ◽  
Random Errors ◽  
Labor Costs ◽  
Express Method ◽  
Thermal Tests ◽  
The Heat Transfer Coefficient

When conducting thermal tests, the purpose of which is to determine the heat transfer coefficient of the body of an isothermal car K, the study of measurement errors affecting the accuracy of the obtained value plays an important role. The results of such experiments may contain various measurement errors that can introduce significant deviations into the resulting values of the desired coefficient. Obtaining accurate results when conducting this kind of experiments is impossible without a preliminary study of the causes that affect the final result. The article presents the types of measurement errors that affect the accuracy of determining the heat transfer coefficient of the body  of an isothermal car when conducting thermal tests. It was noted that the magnitude of labor costs and energy losses during the further operation of this body significantly depends on the accuracy of the value of this coefficient. It was emphasized that one of the main types of random errors arising from measurements and compliance with the established procedure for conducting typical thermal tests is a voltage drop (“slump”) in the electrical network, leading to significant errors in the calculations of the heat transfer coefficient of the isothermal car body. The values of this coefficient are presented, which were obtained as a result of heat engineering tests performed using the equilibrium mode method and the express method. It is shown that the use of the express method to determine the heat transfer coefficient of the bodies of isothermal cars reduces the risk of random errors due to the minimum experiment duration (from 5.5 h), allows to obtain exact values of the desired coefficient (with an error not higher than 3 % of its value of long-term equilibrium method) and use this data for practical purposes.

scholarly journals Determination of long-term permissible currents in wires of power supply systems of railways

2019 ◽  
Vol 78 (2) ◽  
pp. 90-95 ◽  
Author(s):  
E. P. FIGURNOV ◽  
Yu. I. ZHARKOV ◽  
V. I. KHARCHEVNIKOV
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Solar Radiation ◽  
Transfer Coefficient ◽  
Surface Area ◽  
Meteorological Conditions ◽  
The Body ◽  
Additional Heating ◽  
The Heat Transfer Coefficient

In the standard for contact wires made from copper and its alloys, the values of long-term permissible temperatures have significantly decreased. This requires recalculation of previously valid values of long-term permissible currents. Authors considered revised method for calculating the long-term permissible currents, based on a more rigorous consideration of the laws of heat transfer and experimental studies of the conditions of heating and cooling of shaped (contact) and stranded wires. Technique is based on heat balance conditions, using which the sources of greatest inaccuracies become such quantities as cooled surface area, influence of wind direction, meteorological conditions, laws of change in heat transfer coefficient, effect on additional heating of solar radiation. Deviations when these indicators are taken into account by existing methods can cause errors of 40 % or more. Formulas for calculating the actual outer surface of stranded and shaped wires are given. The inadmissibility of calculating the surface area of the wires by their reference diameter is noted. Updated law of the change in heat transfer coefficient for stranded and shaped wires, as well as the degree of its dependence on wind speed and cooled surface, is given based on a summary of extensive domestic and foreign research. It is shown that with the longitudinal direction of the wind, the reduction of this coefficient occurs to a lesser extent than has been assumed so far. Authors propose method for taking into account an increase in the heat transfer coefficient under meteorological conditions characteristic of ice formation. The heat transfer coefficient of shaped and stranded wires in no case can not be taken as for round pipes with smooth surface. Existing method of accounting for solar radiation, which influences the additional heating of wires, leads to an unjustified and repeated exaggeration of this effect, since previously only the radiation incident on the wire was taken into account in the calculations. According to the laws of heat transfer, the temperature of the irradiated body does not depend on the incident, but on the resulting radiation, defined as the difference between the radiations incident on the body and emitted by it in accordance with its temperature. A formula for accounting for such heat transfer is proposed. The above methodology and calculation formulas allow performing reasonable calculations to determine the long-term permissible currents of individual stranded and shaped wires, as well as the contact network as a whole.

scholarly journals Development of an algorithm for determining the heat transfer coefficient of the body of an isothermal vehicle based on the results of analysis of the heat exchange processes occurring in it

2017 ◽  
Vol 76 (5) ◽  
pp. 306-311 ◽  
Author(s):  
A. A. Golubin ◽  
S. N. Naumenko
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchange ◽  
Transfer Coefficient ◽  
Thermal Imaging ◽  
The Body ◽  
Internal Heating ◽  
Heating Method ◽  
Exchange Processes ◽  
The Heat Transfer Coefficient

The article analyzes the heat exchange processes the thermal imaging method using a thermal imaging device. An occurring in the body of an isothermal vehicle when determining algorithm for determining the heat transfer coefficient is proposed, the heat transfer coefficient K by the internal heating method. which makes it possible to calculate its value with an accuracy not The differences are shown in the values of the heat transfer coef-exceeding 5 %, which is regulated by a number of international ficients obtained by the equilibrium internal heating method and normative documents, while reducing the duration of the experiment by at least 6 times. The study gives comparative experimental data and results of calculating the unknown values of K for bodies of isothermal vehicles obtained by the equilibrium method and an express method based on the algorithm described in the article. It is shown that the use of the algorithm for calculating the heat transfer coefficient of the body of an isothermal vehicle will not only increase the productivity of testing stations, but will also lead to the organization of an electronic passport for the thermotechnical state for each body of an isothermal vehicle, the control of which will enable timely diagnosing the thermo-technical condition of the bodies of isothermal vehicles, providing energy-optimal operating modes of energy equipment and, hence, increasing its resource.

Cooling and heating of the fluid in the cylindrical volume

2022 ◽  
pp. 15-26
Author(s):  
Stanislav Tkachenko ◽  
Olha Vlasenko ◽  
Nataliia Rezydent ◽  
Dmytro Stepanov ◽  
Nataliia Stepanova
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Water Environment ◽  
Experimental Studies ◽  
The Body ◽  
Thermal Mode ◽  
Limited Information ◽  
Characteristic Features ◽  
Cylindrical Volume ◽  
Further Development

Experimental studies of the non-stationary heat exchange in the system «environment I – body II» have been carried out. It is established that in the body II, which consists of the fluid and thin-walled metal envelope, the characteristic features of the regular thermal mode occur, i.e., cooling (heating) rate of the body II- m = const; heat transfer coefficient between the water (environment I) and body II is practically stable α1 = const; uneven temperatures distribution coefficient in the body II ψ = const. This new notion of the heat transfer regularities in the body II is planned to apply for further development of the experimental-calculation method for the forecasting of the heat exchange intensity in the compound fluid media with limited information regarding thermophysical and rheological properties.

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